To understand on the molecular level the processes involved in the initiation and regulation of nerve impulses, work is in progress to elucidate the importance of ion in the function of excitable cells. These results will be correlated with the work of electrophysiologists using electrical measurements, and with our own studies of ligand binding to acetylcholine receptor protein molecules. BIBLIOGRAPHIC REFERENCES: Hess, G.P., Andrews, J.P., and Struve, G.E. Biochem. Biophys. Res. Comm. 69, 830-837 (1976). Apparent cooperative effects in acetylcholine receptor-mediated ion flux in electroplax membrane preparations. Donner, D.B., Fu, J. -j. L., and Hess, G.P. Analytical Biochemistry (1976). In press. Equilibrium dialysis of the membrane-bound acetylcholine receptor: a simple method to avoid common errors.